At USC, Troy was a 3-year starter who also saw some playing time at linebacker his freshman year. A very physical player, he developed a reputation for sacrificing his body to make the hit as well as being a team leader. When playing the run, he has great ability to move sideline-to-sideline. He impressed with his pass coverage also, with fluid movement and back-pedaling, and sound decision-making during the play.

Troy was named All-American and All-Conference both his junior and senior years. Over his outstanding senior year, he registerd 68 tackles, 1 interception,4 pass defenses, and 12 tackles behind the line of scrimmage. One of three finalists for the 2002 Thorpe Award, he is hailed as the school's finest defensive back since the Ronnie Lott era (1977-80).